Abstract
Idealized high-resolution numerical simulations of tropical cyclogenesis are presented in a model that represents deep convection by a warm rain process only. Starting with an initially weak, cloud-free, axisymmetric warm-cored vortex (maximum wind speed 5 m s(-1) at a radius of 100 km), rapid vortex intensification begins after a gestation period on the order of 2 days. From a three-dimensional perspective, the genesis process is similar to that in the rotating convection paradigm for vortex intensification starting with a much stronger initial vortex (V-max = 15 m s(-1)). The patterns of deep convection and convectively amplified cyclonic relative vorticity are far from axisymmetric during the genesis period. Moreover, the organization of the cyclonic relative vorticity into a monopole structure occurs at relatively low wind speeds, before the maximum local wind speed has increased appreciably. Barotropic processes are shown to play an important role in helping to consolidate a single-signed vorticity monopole within a few hours near the intensification begin time. The rotating convection paradigm appears adequate to explain the basic genesis process within the weak initial vortex, providing strong support for a hypothesis of Montgomery and Smith that the genesis process is not fundamentally different from that of vortex intensification. In particular, genesis does not require a trigger' and does not depend on the prior existence of a mid-level vortex.
| Item Type: | Journal article |
|---|---|
| Faculties: | Physics |
| Subjects: | 500 Science > 530 Physics |
| ISSN: | 0035-9009 |
| Language: | English |
| Item ID: | 55757 |
| Date Deposited: | 14. Jun 2018, 10:00 |
| Last Modified: | 04. Nov 2020, 13:36 |
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